共查询到20条相似文献，搜索用时 140 毫秒
1.
杨树抗云斑天牛新品种选育材性性状遗传分析 总被引：3，自引：0，他引：3
格性直接影响木材的用途及其经济价值。材性育种已成为现代林木育种的一个重要内容。世界各国都非常重视。木材密度和纤维长度是主要的两个材性特征,往往是林木材性改良的两个性状。木材密度直接影响木材物理力学性质,木材纤维长度和长宽比直接影响纸浆和纸的质量。研究木材密度和木材纤维特性的遗传变异规律,有助于指导林木材性育种工作。本文报道I-69杨×I-63杨F1杂种无性系木材性状遗传变异的研究结果。 相似文献
2.
首次采用非破坏性测定木材材质方法、并用立木木材弹性系数指标来研究９年生马尾松不同家系间材性的差异,取得了较理想的结果,初步说明了立木木材弹性系数在马尾松材性育种上的应用是可行的,同时提出了应用该技术时的一些注意事项,丰富了我国木材材质的测定方法。 相似文献
3.
4.
5.
介绍了澳洲开展辐射松木材材性遗传变异研究的背景、最新成果及其研究条件和手段。其研究表明:基因控制木材的材性,生长环境对木材密度影响不明显,木材数量性状指标与质量性质指标之间存在负相关,生产中可通过一定的手段来预测立木的木材质量。但利用分子技术要想改良材性而又不损失生长量将面临很大挑战,因此从长远考虑,把减小遗传负相关和优化选择指标相结合,是辐射松材性育种的首选策略。 相似文献
6.
7.
对马尾松造纸材遗传改良和选择育种已有研究成果进行综合阐述。在明确马尾松造纸材育种目标的基础上，系统阐述了其木材产量、木材质量和浆纸性能在种源、林分、家系、个体和个体内各层次的变异模式和规律，以及性状遗传、遗传相关和遗传稳定性等遗传参数。通过木材量质与浆纸性能的联合选择，确定福建西部、江西中南、湖南南端、广东西北和广西东南这个呈东北─西南走向的狭长区域是马尾松造纸材最优种源区，而江西崇义，广西岑溪，广东罗定、英德、韶关和福建永定则是其最佳产地。同时选择了一批生长、材质兼优的家系和个体。最后就马尾松造纸材选择育种策略和未来遗传育种研究的重点提出意见。 相似文献
8.
9.
10.
介绍世界各国的松树材性改良的概况及研究进展,材性研究包括木材基本密度遗传变异、木材纤维形态遗传变异、木材化学组成遗传变异和木材材性性状之间相关性,并提出了马尾松纸浆材遗传改良的策略。 相似文献
11.
小径原木是当今世界上主要的木材资源之一,各国均在积极开发利用。文内着重介绍了林业发达国家在研究小径原木的材性特征和主要产品加工工艺特点等方面所取得的成果和经验。 相似文献
12.
13.
以胸径、树高、材积为数量评价指标,结合干形、冠高比和分枝粗细形质指标,采用5株优势木对比法开展了西南桦人工林的优树选择技术研究。通过对西南桦人工林10 21年生不同林龄阶段的优树选择标准的总结,提出了优树选择标准,即优树胸径、树高、单株材积分别大于5株对比优势木平均值的9%11%、5%7%、26%31%以上,形质指标综合得分大于7.5,共选择出西南桦优树37株,入选率为33.9%。西南桦优树的选择标准在实际应用中可根据林分状况适当调整,选优即要考虑其生长性状,同时注意材性、抗性的选择以保证西南桦育种群体的遗传多样性。 相似文献
14.
关于发展人工林与建立人工林业问题探讨 总被引：13，自引：1，他引：12
全世界森林面积为 34 5 4× 1 0 8hm2 ,其中 3%是人工林。人工林是重要的森林生态系统 ,在木材生产、环境保护和景观建设中具有重要功能和作用。人工林在生产功能方面的补偿作用 ,使天然林可以更好地发挥生态环境价值、森林娱乐和生物多样性保护功能。人工林可持续经营的前提是遗传材料的正确选择与营林实践艺术的结合以及保证这种结合的林业政策。愈来愈多地使用外来树种营建人工林是全球趋势。人工林对于环境和生物多样性的影响 ,可以通过合理的规划和经营措施得到解决。林木育种与遗传改良和经营制度的技术创新是不断提高人工林生态系统生产力的动力。人工林的可持续经营是一个十分复杂的问题 ,中国人工林实现可持续经营面临技术和体制两方面的挑战 ,但是 ,根本出路在于林业经济体制的改革 ,象农业那样 ,在市场经济环境中实行人工林产业化经营 ,建立人工林业 (Forestplantationindustry)。 相似文献
15.
Wood energy plantations are being considered in several countries for achieving greater energy independence. Many of the projects are still in research and development stages, while several programs are already operational.Maximizing the efficient production of energy by means of optimizing the growth of selected plant crops is the goal in energy plantations. For this, the bioecological factors (planting site, tree species, photosynthetic activity, soil moisture and nutrient availability), methods of genetic improvement (interspecific hybrids, clones, breeding for biomass productivity and qualities, and breeding for energy efficiency), and cultural treatments (soil preparation, planting stock, planting, spacing, weed control, fertilization, irrigation, pest control and resprouting) influencing productivity are discussed. A review of biomass yields, energy contents and ratios, production economics and conversion methods concludes the treatise.Short rotation, intensively managed plantations of genetically improved, fast growing trees can make significant contributions to energy supplies. The increased support given to this concept of energy plantations will benefit forest management in general.The environmental concerns related to intensive cultural practices in energy plantations are similar to those in agriculture. The problems are not impossible to overcome. Compared to hazards of nuclear energy, and polluting effects of coal, wood biomass remains undoubtedly a safer and healthier option. 相似文献
16.
《Southern Forests》2013,75(3):171-178
Plantations consisting of non-native tree species were established on the Copperbelt of Zambia to supplement timber supply from natural forests and to meet the increasing demand of round wood and fuel wood for the copper mines. In early 2004, a disease characterised by severe leaf defoliation and death of juvenile trees suddenly occurred in plantations of the Copperbelt Forestry Company. This study was undertaken to determine the nature of the disease and extent of damage caused with a view of providing a framework for sustainable management of the plantations. Disease incidence, severity and impact on plantations using the crown damage index were assessed for three consecutive years. Eucalyptus grandis was more affected than E. cloeziana and leaf spot incidence and severity were higher in Kalibu, Kitwe District, than in Kafubu, Kalulushi District. The incidence in Kalibu was 90.4%, causing tree crown damage of 18.6% at the end of the assessment in 2006 compared to 17.5% incidence and 1.02% crown damage recorded in Kafubu. Fungi collected from leaf tissues included species of Aulographina, Cryptosporiopsis, Cylindrocladium and fungi in the Teratosphaeriaceae. Stem pathogens were identified as fungi in the Botryosphaeriaceae and Kirramyces sp. Diseases induced by these pathogens are increasingly becoming major threats to young eucalypts, resulting in poor stem form. Factors favouring disease development are described and these need to be properly managed to minimise the impact of diseases in addition to the need to establish selection and breeding programmes to develop tolerant genotypes to ensure a sustainable future for the forestry industry in Zambia. 相似文献
17.
国外制浆材树种遗传改良研究 总被引：4，自引：0，他引：4
世界年工业用材中的1/4～1/3用于制浆和造纸,一些国家把制浆和造纸工业作为本国的支柱工业来发展。为提高在世界市场上的竞争力,他们已致力于提高纸浆材树种的遗传改良,以使木材培育与木材加工业的终点产品对材性的要求有机地结合起来。使育种的经济目的更为明确。试图对制浆材树种的遗传改良做一简述,以推动我国林木育种事业向更高水平发展。 相似文献
18.
《Scandinavian Journal of Forest Research》2012,27(7):681-691
Abstract Genetic selection in forest tree breeding requires multiple traits to be considered simultaneously. Based on an economic breeding objective, traits are weighted according to their economic importance to create an index used for selection. Economic breeding objectives have mainly been developed in animal breeding and have only recently been applied to forest tree breeding. A review of the general methodology highlights the decisions associated with developing economic breeding objectives and their effects. Furthermore, studies concerning economic forest tree breeding objectives provide a bulk of knowledge and practical experience for fast growing, short rotation species. We have identified and discussed challenges when applying this methodology in Swedish tree breeding. Major challenges are: (1) managing the uncertainty of future industrial uses of wood and industrial processing, originating from long rotations; (2) various issues associated with having a production system describing an entire nation; (3) the size and effects of the discount rate; (4) developing models capable of representing genetic changes in the complex and dynamic system of growing and harvesting trees. We believe that these challenges must be tackled by a joint multi-disciplinary effort, involving stakeholders and researchers in several areas (e.g. forest genetics, economics, wood engineering), to make significant progress. 相似文献
19.
杨树短轮伐期集约栽培的新进展 总被引：8，自引：0，他引：8
本文介绍了参加18届国际杨树会议的17个会员国的杨树栽培新进展、杨树育种和短轮伐期集约栽培的研究动态和成果,还报道了与会外国专家的观感。 相似文献
20.
本文综述了国内外桉树人工林无节材培育修枝技术的理论和研究。为了满足当今社会对高品质木材的大量需求,人们开始将桉树纸浆材人工林栽培向更高价值含量的锯材转化。众多研究表明,影响桉树木材外观等级的主要因素是节子。要从根本上解决木材质量的问题,合理而科学的修枝理论和实践显得尤为重要。修枝直接影响树冠动态发展,而树冠动态与树木的生长直接相关。尽管桉树自然整枝能力较强,但不能靠它获得大量无节材,修枝措施必不可少。修枝对树木生长和木材材质都会产生影响。合理的修枝强度会促进树木生长,而科学的修枝技术对高品质无节材的形成相当关键。为了使修枝达到最大效益,在非生长季节以及树冠郁闭前修去小枝活枝,并且保证修枝伤口平滑和注意伤口保护是最合适的修枝处理。伤口的愈合与诸多因素有关。 相似文献